Electric clock



A. F. POOLE ELECTRIC CLOCK Aug 3, 1937.

Filed Jan. 5, 1951 FM):- PEGUMTED weEE/vrwmea wAUZ M Patented Aug. 3, 1937 UNITED STATES PATENT OFFICE ELECTRIC CLOCK Application January 5, 1931, Serial No. 506,561

22 Claims.

My invention is an electric clock. The object of my invention is to provide a clock which is adapted to be run from a regulated alternating current and which shall continue to move during periods of interruption to the current. A further object of my invention is the provision of a clock movement in which the Vibrating timing member, such as the balance wheel or pendulum, is forced to make vibrations, not as determined by the hair spring in the one case or gravity in the other, but by a force which is periodically applied to the vibrating member. In other words, the timing member of the clock is brought into synchronism with a periodic source. In the embodiment of my invention herein shown, this periodic source is a synchronous motor run in step with a regulated alternating current. By the term regulated alternating current, I mean a current which is ordinarily used by light and power service but which is regulated at the power house so that the average number of vibrations sent out in a given time shall be some predetermined amount. For example, a number of power stations regulate their current so that in the long run exactly 60 cycles per second are sent out. This regulated current serves to drive synchronous motors running in step therewith and these motors are geared by appropriate gearing to move a pair of clock hands. My invention will be best understood by reference to the following figures, of

which Fig. 1 is a diagrammatic view of one embodiment of my invention, Fig. 2 is a modification thereof, and Fig. 3 is my invention as applied to a pendulum instead of the balance wheel as shown 5 in Fig. 1. All of the drawings are more or less diagrammatic, but will be clear to those skilled in this particular art.

Referring now to the drawing, I have provided a balance wheel l3 mounted on the shaft II to which is attached a hair spring l2, one end l3 of which is attached to a rod 4 rigid in a bell crank lever l5 rotatably mounted on a shaft I6 which is colinear with the bell shaft The bell crank l5 has an arm H which is connected by a link I8 to a pin |9 in a gear 20 meshing with a gear 2| on a shaft 22 on which is the synchronous motor 23. The motor 23 may be any of the types well known in the art. It is preferably a motor of the self-starting type in which there is provided a set 5 of poles to be kept in step with the current and also some kind of a retarding winding in order to give the motor a starting torque. For use in my herein described invention, it is desirable that the motor start itself, although this is not necessary.

55 I shall now describe the means for keeping the balance wheel ID in motion. On the shaft 22 there is provided a pinion 28 meshing into a gear 29, rigid with which is a pinion 39 meshing into a gear 3|, rigid with which is a pinion 32 meshing into a gear 33, rigid with which is a pinion 34 meshing into a gear 35, all of the above mentioned gears being rotatably mounted in the framework. A gear 31 is in mesh with a gear 33, and is also in mesh with the teeth 38 on the spring barrel 39 which is rotatably mounted on a shaft 43. Frictionally engaging the inside of the barrel 39 is a spring collar 4| to which is attached the end of the driving spring 40, the inner end of which is attached to the shaft 43. Obviously, rotation of the motor 23 will result in rotation of the barrel 39, and consequent winding of the main spring 40 until this spring has reached a certain tension at which point the collar 4| will start to slip inside of the barrel 39.

Rigid on the shaft 43 is a gear 44 which meshes with the gear 45, this last mentioned gear being the central wheel of the clock movement. The gear 45 meshes with a pinion to which is attached a gear wheel meshing with a pinion 52 on a gear wheel 5| which meshes with a pinion on the escape wheel 53. The escape wheel 53 drives the customary pallets 54 mounted on a shaft 55 on which is mounted the customary fork which engages with the roller pin 51 rigid on the balance l0.

From the above it will be clear that the spring will furnish power to oscillate the balance lil under the influence of the hair spring l2. The rate of rotation of the main spring barrel 39 is greater than that of rotation of the shaft 43. Consequently, the barrel 39 will be wound by the motor 23 faster than the spring 40 is unwound by the rotation of the shaft 43. Consequently, the motor 23 overwinds the clock movement, but such excess winding is taken care of by means of the friction connection between the collar 4| and the spring 40. After the spring has been wound to a certain tension, it simply slips in the barrel.

It will be apparent that'the end of the spring l3 will be moved to and fro in synchronism with rotations of the gear 20. Consequently, the balance Ill will be forced to make its vibrations in unison with this motion. The gear ratio 20 to 21 is so proportioned that the rate of rotation of the synchronous motor 23 is changed so that when the end I3 is vibrated at a certain rate the hands 41 and 48 of the clock will keep time. To put the matter in another way, if the end I3 is immovable, the balance l0 when driven by the spring 40 will keep time within a half minute or so a day. In

' said lever.

order to do this, this must have a certain period of vibration which is usually two complete oscillations per second. Now, the gearing 2|] to 2| is so proportioned that the bell crank [5 will make two complete oscillations per second also when the synchronous motor 23 is running up to speed. Consequently, any slight tendency of the balance In to depart from this frequency, either fast or slow, will be corrected by the motion of the end l3, and the balance II) will be kept in synchronism with the speed of the synchronous motor 23.

During the time that current is on, the motion of the clock hands 41 and 48 will, of course, be determined by the speed of the synchronous motor which in its turn is determined by the frequency of the current sent out from the power house, the synchronous motor being connected by leads 24 and 25 to the power mains 26 and 21 which supply regulated current from a source A. In the event the current is interrupted, such as by blowing out of a fuse, interruption to the wire service, trouble at the central station, or any other cause, the balance wheel Ill will vibrate, being driven by the spring 40, at its own rate, and since this rate is determined beforehand so that the clock will keep approximate time, the only error in this clock will be the amount that the balance wheel I has varied from the previous rate during the period of current interruption. In order to regulate the balance wheel I0 I have provided the regulating screws 60 and GI in the circumference thereof.

In Fig. 2 I have shown a modification of the mechanism described above in that the bell crank IT, instead of being moved in approximately sim-- ple harmonic motion by the rotation of the wheel 20, is moved by a different cam motion. To this end of the motor 23 which drives the shaft 22' drives also the gear 2| rigidly attached to the shaft 22. A gear 20 is rigidly attached to the cam disk 63 and rotates it. The cam disk 63 is provided with a groove 64 in which rides a roller 62 attached. to the arm ll of the bell crank l rotating on the shaft 16' which, as above noted, is colinear with the balance shaft II. The pin [4' which is rigidly fixed in the arm moves the end hair spring the same as in Fig. 1. By means of the cam 64 I am able to give a quick motion to the end of the balance spring instead of a gradual one as is given by the mechanism in Fig. l, and by properly shaping the cam I am able to move the end of the balance spring in any predetermined manner.

In Fig. 3 I have shown my invention as applied to a pendulum. In this figure there is a pendulum 65 swinging about a support 66 and having attached to the side thereof a synchronizing spring 61. A lever 68 pivoted at 69 acts on the spring 64. The lever 68 is oscillated by a synchronous motor, through the link l8 as the bell crank [5 of Fig. 1, is oscillated, and as the period of the pendulum E5 is approximately equal to the period of oscillation of the lever 68 the pendulum 65 will be kept in synchronism with the motion of In the pendulum device the spring 61, of course, has in part the same function as the spring l2 in Fig. 1. However, the period of the pendulum 65 is determined in the main by the force of gravity, the spring 6'! simply applying the slight correction to this force needed to keep the pendulum in synchronism.

Many changes and variations may be made from my herein described invention without departing from the spirit thereof, since I claim:

1. In an electric clock, the combination of a vibrating member, elastic means connected to said vibrating member and moving therewith, a synchronous motor, a source of current of regulated frequency driving said synchronous motor, and a continuous connection between said synchronous motor and said elastic means whereby said vibrating member is kept in step with said source of regulated current approximately throughout every vibration of said member.

2. In an electric clock, the combination of a synchronous motor, a source of power for said clock, a vibratory member in said clock, means operated by said source and operating said vibratory member, elastic means connected continuously to said vibratory member, and means continuously connecting said synchronous motor and said elastic means whereby said synchronous motor varies the force of said elastic means in timed relation to the operation of said motor.

3. In a clock, a clock train, a vibratory time measuring device regulating the rate of operation of said clock train and adjustable to vary said rate, means continuously applying a substantially continuous driving force to said clock train, a source of alternating current of commercial frequency whose alternations are regulated in accordance with time intervals, and means controlled by said alternating current and including an element vibrating in timed relation to the alternations of said current and in substantial phase with said device through approximately each complete vibration thereof, for controlling said time measuring device throughout approximately each full vibratory cycle of movement in I a manner to compel operation of said regulating device in a definite timed relation to the alternations of said source of current.

4. In a clock, a clock train, means including a balance wheel for regulating the operation of said clock train, a hair spring controlling the vibration period of said balance Wheel, means for applying a driving force substantially continually to said clock train, a source of pulsating current whose pulsations are regulated in accordance with time intervals, means operated by said current in timed relation. to the pulsations thereof and connected to said hair spring for varying the tension of said hair spring in timed relation to the pulsations of said current, whereby the operation of said clock train will be in timed relation to the pulsations of said current.

5. In a clock, a clock train, means including a continuously operating pendulum for regulating the operation of said train, an elastic element operative upon said pendulum to modify its rate of operation, a source of pulsating electric current whose pulsations are regulated in accordance with time intervals, and means controlled by said current in stressing said elastic element at any position within approximately the entire arc of movement of said pendulum and in timed relation to the pulsations of said current, for keeping said pendulum yieldingly in vibration and in synchronism with said pulsations.

6. In an electric clock, the combination of a source of alternating current, a balance vibrating under the influence of a hairspring, means to drive said balance, a synchronous motor running in step with said current, and means actuated by said motor periodically to vary the tension of said spring approximately in step with the vibrations of said balance, whereby said balance is kept in step with said current.

iii

7 In a clock or the like, a vibrating time measuring member having a natural period approximately at the rate desired, means for keeping said member in vibration continuously, a source of alternating current, means operated by said current in timed relation to the alternations thereof and having an element vibrating at the rate desired for said member in a path substantially parallel to the path of said member and approximately in phase with said member and means effective approximately throughout the entire amplitude of vibration of said member and acting between said member and element for keeping said member substantially in phase with said element.

8. In a clock or the like, a vibrating time measuring member having a natural period approximately at the rate desired, means for keeping said member in vibration continuously, a source of alternating current, means operated by said current in timed relation to the alternations thereof and having an element vibrating at the rate desired for said member in a path substantially parallel to the path of said member and approximately in phase with said member and elastic means effective approximately throughout the entire amplitude of vibration of said member and acting between said member and element for keeping said member substantially in phase with said element.

9. In a clock or the like, a motor having a regulating member moving approximately at the rate desired, means for keeping said motor in operation, a source of alternating current, means 1 controlled by said current for operation in timed relation to the alternations thereof and having an element moving at the rate desired for said member, in a path substantially parallel to the path of a part of said member, and approximately in phase with said member, and means effective throughout approximately the entire amplitude of vibration of said member, and acting between said member and element to keep said member substantially in phase with said element and operating at exactly the same rate, whereby said member will be kept in operation by said motor, and accurately regulated by said current controlled means.

10. In a clock, a vibrating member, a source of current of time regulated frequency, means mechanically connected to said member and controlled by said current and effective at every point throughout substantially the full arc of movement of said member, for applying periodic forces of time regulated frequency to said member, to bring it into synchronism with said forces, whenever the period of said member tends to deviate from the frequency of said forces.

11. In a clock, a vibrating member, a source of current of time regulated frequency, means controlled by said current and having a part vibrating in timed relation to the frequency of said current, and at the desired rate of vibration of said member, and resilient means acting between said member and said part and effective at every point throughout substantially the entire arc of movement of said member for maintaining the rate of vibration of said member in said timed relation to said current frequency.

12. In a clock the combination of a vibrating member having a natural period of vibration and including an elastic means, a synchronous motor operating in approximately timed relation to said member, and a physical connection between said synchronous motor and said elastic means continuing throughout the complete vibration of said vibrating member to vibrate said elastic means in step with said motor, and keep said member vibrating in synchronism with said motor.

13. In an electric clock, a synchronous electric motor, a time regulated source of power for said motor, a clock train having time indicating means, said clock train having a vibratory time measuring element including an elastic member, means driving said clock train, and means controlled by said motor and in turn operative on said elastic member and effective thereon at each point throughout the entire arc of movement of said vibratory time measuring element at regular intervals to modify the stress which said member exerts on the remainder of said vibratory element for insuring vibrations of said vibratory element at a rate bearing a definite time relation to the operation of said synchronous motor, whereby during operation of said motor, said motor will control the rate of operation. of said clock train, and in the event of interruptions in said source of power, said clock train may continue to operate at substantially the same rat-e for a considerable period after the inter- K ruption or until said motor resumes its operation.

14. In an electric clock, a clock train having a vibratory time measuring element including a resilient device, said vibratory element being adapted to operate continuously and approximately at a desired rate, a time regulated source of periodic electric current, and means operated by said source and operating said resilient device at intervals having a definite time relation 1,.

to the periodicity of said current and throughout approximately any part of a complete vibration of said element to change its effect on said element and cause operation of said vibrating element at a rate such that the operation of said clock train will bear a predetermined and definite relation to the periodicity of said source of current.

15. A clock comprising a. clock train having a vibrating time measuring element including an elastic member, a mechanical motor operating said clock train by stored energy, a source of time regulated current, a synchronous motor operated by said current, and means operated by said motor for varying the stress in said elastic member throughout each complete arc of vibration of said time measuring element regularly in timed relation to the time regulation of said current and thus regulating the rate of operation of said clock train in a definite timed relation to the operation of said synchronous motor.

16. In a clock, a vibrating time measuring member, a source of time regulated alternating current of commercial frequency, a synchronous motor operated by said current, means driven by said motor and having an element vibrated at uniform periods thereby, at a rate approximately that of said vibrating member and in sub stantial phase therewith, said element being adapted to operate upon said vibrating member at approximately any position of said member during its complete vibration cycle to keep said member vibrating substantially in phase with said element, whereby said member will vibrate at a definite time rate with respect to said synchronous motor.

1'7. In an electric clock, a vibrating time measuring member including an elastic element, a source of alternating current of commercial frequency having time regulated alternations, and

means including an element acting on said elastic element and continuously connected thereto controlled by said current to operate substantially in phase with said member throughout approximately the entire vibratory movement of said member, and keep said measuring member vibrating in timed relation to the alternations of said current and at a rate having a definite timed relation to the alternations of said current.

18. In a clock or the like, a vibrating time measuring device, having a selected natural period of vibration, a source of alternating current of commercial frequency whose alternations are regulated in accordance with time intervals, means operated by said current in timed relation to the alternations of said current for vibration thereby at a rate approximately corresponding to the rate of vibration of said device, said current operated means being connected to said device so as to be operative at approximately any point in a complete cycle of vibration of said device for transferring stresses between them and compelling operation of said device in synchronism and in phase with the vibration of said means.

19. In a clock, a vibrating member including an elastic element, a source of electric current having periodic time regulated pulsations of com mercial frequency, and means controlled by said current and continuously operative upon said elastic element for movement therewith in timed relation to the pulsations of said current and in approximate phase with said member throughout approximately a complete vibration of said member for keeping said member vibrating at a dellnite rate having a uniform relation to the pulsations of said current.

20. In a clock, a self-operating clock train having a vibrating element including elastic means, said element being kept in vibration by said clock train and in turn controlling the rate of operation of said train, a source of pulsating current whose pulsations are regulated in accordance with time intervals, a motor controlled in its rate of operation by said current, and having a member moving in a timed relation to the pulsations of said current and approximately in phase with said element throughout approximately each complete vibration thereof, said member being adapted to operate upon said elastic means throughout approximately each complete cycle of vibration of said vibrating element, of which said elastic means forms a part, for transmitting energy between said element and said member when they get out of phase in such a manner as to keep them always in phase.

21. In a clock, a vibrating member, a source of current of time regulated frequency, and mechanical means controlled by said current having a timed relation to the frequency of said current and connected to said member for mechanically applying periodic forces to said member, and effective thereon at every point throughout substantially the entire arc of movement of said member, to bring its rate of vibration. into synchronism with the frequency of said periodic forces whenever the frequency of said member tends to deviate from the frequency of said forces.

22. In a clock, a vibrating member, a source of current of time regulated frequency, an elastic member, and mechanical means controlled by said current and connected to said vibrating member through said elastic member for mechanically applying periodic forces of time regulated frequency through said elastic member to said vibrating member, whereby said mechanical means is effective on said vibrating member throughout substantially the full arc of movement of said vibrating member, to bring it into synchronism with said forces, whenever the period of said member tends to deviate from the frequency of said forces.

ARTHUR F. POOLE. 

